Galapagos Islands Wildlife Guide

The abundance of friendly and plentiful wildlife makes the Galapagos Islands a perfect destination for animal lovers. One of the greatest aspects of the trip to the islands, from a visitor’s point of view, is the fact that the animals living there are extremely tolerant of our presence; in fact, they have no natural fear of humans and allow us to approach them at close range.

Explore the Wildlife of the Galapagos Islands:

Learn about friendly Galapagos sea lions and fur seals, as well as whales and dolphins.

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Mammals

Due to its isolated locale far from the mainland, that Galapagos Islands boast only six species of land mammals. This unique ecosystem supports two types of bat and two types of rice rats, all of which you are not likely to encounter on your journey. In contrast, the two other species— Galapagos sea lions and Galapagos fur seals—will typically appear often during your Galapagos adventure.

GALAPAGOS SEA LION

The most common native mammal that you will see during your journey is the Galapagos sea lion, a subspecies of the Californian sea lion, which inhabits most islands. There are an estimated 50,000 individuals in the Galapagos. Territorial bulls can reach up to 550 pounds and have exhibited aggressive behavior, including chasing swimmers from the water and biting people if harassed, so do not approach them too closely. On the other hand, females and pups are extremely spirited, and will often have fun swimming with snorkelers. Typically, sea lions live to the age of 20. Females reach sexual maturity at age 5; males are capable of mating then too, but usually do not do so until they are older. Dominant males patrol and guard particularly attractive beaches, territories which may contain up to thirty females. The dominant male will have mating access to these females, but only for as long as he is able to keep other males at bay. Defending a territory is very demanding work, and males may go for days without getting much food or sleep. After several weeks putting up this front, a harem-master may become weary and susceptible to defeat causing him to lose his position to a new, well-rested male.

Females become sexually receptive once a year. The gestation period lasts 9 months and the (usually) solitary pup is born around the beginning of the dry season. After nursing for a week, the mother will return to the water to feed. Thereafter, she will continue nursing, after her fishing trips, until the pup is 5 or 6 months old, when it learns to fish on its own. Even then, the pup will continue to supplement its diet with its mother’s milk; some females may even nurse two pups, born in subsequent years, at the same time. « Back to top

GALAPAGOS FUR SEAL

You will see the endemic Galapagos fur seals less frequently than the sea lions, which they resemble only superficially. Upon closer inspection, however, fur seals are quite different from sea lions. They are smaller and have a wider and shorter head shaped like a bear. A fur seal’s ears are also more prominent, and their front flippers are bigger than sea lions. Fur seals and sea lions share many similar mating and social behaviors. One main difference is that male fur seals tend to defend territory from the land, while male sea lions defend from the water.

The fur seal’s coat is very dense and luxuriant, consisting of two layers of hair. This attracted the attention of sealers who decimated the population in the 1800s while hunting for the valuable skins. Because of their thick fur, the animals hunt at night and spend the hot part of day hiding out in cool caves. This secretive behavior helped the species survive the sealers’ depredations. Today, fur seals are fully protected and have completely recovered; there are currently almost as many fur seals as sea lions, but the more elusive habits of the former explain why visitors see them less often than sea lions. « Back to top

BOTTLENOSE DOLPHIN

While not native to the Galapagos, the bottlenose dolphin is a frequent visitor to the islands. They can appear any time the boat is moving and often put on shows that delight travelers. Their distance from the boat will vary greatly; some will frolic beside the vessel, others will dance near the bow, and still others will execute flips off on the horizon. If you see them at night, the dolphins cause the ocean to shimmer with bioluminescence as they churn up thousands of miniscule phosphorescent beings, which glow when disturbed. Less frequently seen are the common and spinner dolphins. An encounter with these highly intelligent cetaceans is truly one of the highlights of any Galapagos adventure. « Back to top

SPERM WHALE

During the 1800s, the sperm whale was hunted to the brink of extinction. The upwelling waters around the islands are perfect feeding grounds for these animals, which were hunted by the thousands as the industrial revolution demanded more oil. When humans began extracting oil from the earth, the sperm whales were spared, but the rich history of the rugged whaling industry remained in the Galapagos Islands. Due to the nature of its diving, it is rare that visitors have the opportunity for an up-close encounter with a sperm whale, but it is not uncommon to see its spout on the horizon or its giant belly rise to the surface in the distance.« Back to top

Discover the fascinating species of seabirds and land birds you'll encounter in the Galapagos.

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Birds

The Galapagos Islands are bounded by endless open sea; it makes sense that seabirds would occupy a prominent place in the archipelago’s fauna. Visitors often see most of the nineteen species (five of these are endemic) who are Galapagos residents. Biologists estimate that up to 750,000 seabirds spend time in Galapagos, including 30 percent of the planet’s blue-footed boobies and the world’s largest colony of red-footed boobies. Only 29 resident species of land birds occupy the Galapagos, but 22 are endemic to the archipelago. Traveling through the Galapagos offers the birding opportunity of a lifetime. Colorful, interesting and entertaining species will enrapture even those who don’t consider themselves ‘birders.’

GALAPAGOS PENGUIN

Unlike most other penguins who inhabit the Southern Hemisphere’s frigid regions, the Galapagos penguin can live farther north than any other penguin in the world due to the cold winds of the Humboldt Current, which originates in Antarctica and flows along the length of the coast of South America. They typically breed on Fernandina and Isabela’s western portion, but visitors frequently see a tiny colony on Bartolome. Periodically, they also appear on James and Floreana. Individuals can breed year-round and under optimal conditions, and they can produce two broods per year. One of the five native seabirds found on the archipelago, these flightless birds form small colonies with dispersed nests. Though clumsy on land, they are extremely skilled and swift underwater, a fact that becomes apparent when you snorkel with them. However, don’t try to match their pace because their agility and speed underwater is unmatched!
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WAVED ALBATROSS

Averaging 3 feet long, weighing up to 11 pounds and boasting an 8-foot wingspan, the waved albatross holds the esteemed position of being the archipelago’s largest bird. Despite its gargantuan proportions, the waved albatross can remain at sea for years without ever touching land and is one of the most graceful flying birds on the planet. With the exception of a small number of pairs breeding off the coast of Ecuador on Isla de la Plata, the whole planet’s population—approximately 12,000 pairs—nests on Hood. After they lay eggs between mid-April and late June, colonies remain active as parents feed their one offspring through December. When the young birds fledge, they leave the nest and stay away for 4 to 5 years. All birds stay at sea from January to March.

Courtship typically occurs during the second half of the mating season. It can occur anytime birds occupy the colony, but October is typically the most active month. During one of the most remarkable ritualized mating displays performed by any bird, the waved albatross executes an impeccably arranged 20-minute “dance” that involves bowing, bill circling, swaying and freezing, honking, bill clicking and whistling. « Back to top

RED-BILLED TROPICBIRD

Its elongated tail streamers—two extended feathers equal in length to the rest of its body—are the most conspicuous feature of the distinctive red-billed tropicbird, which measures 2.5 feet in length with tail feathers, and has a wingspan just under 3.5 feet.

When seen at close range, the coral-red bill and black eye stripe stand out. They often take to the wing in small clusters, where they demonstrate their graceful flying techniques and alert you to their presence with a characteristic, penetrating screech. On the majority of islands, they nest in fissures and holes in piles of rocks or crags, but visitors usually see them from paths traversing cliff tops, like those found on Genovesa, South Plaza and Hood. Faraway out at sea, they feed by plunging into the water hoping to snag fish and squid.« Back to top

BROWN PELICAN

Its giant pouched bill and enormous size (4 feet long with a 6.5-foot wingspan) make this bird immediately recognizable. As such, it is usually the earliest bird identified by visitors. Nesting year-round on most islands, they are usually brown, but adults develop bright white and chestnut head and neck markings throughout the breeding season.

Broad fingered wings make these pelicans excellent gliders, and they often fly in a squadron-like formation, flapping their wings and soaring in harmony to produce a graceful floating ballet. They utilize a fascinating method for feeding that requires great skill and is difficult for birds to master. First, they dive into the shallows and scoop water—up to 2.5 gallons—into their pouches. As water swiftly flows out through their bill, they swallow trapped fish. Though broods regularly consist of two or three chicks, numerous fledglings are incapable of learning the scoop-fishing technique rapidly enough so they die of starvation. « Back to top

BLUE-FOOTED BOOBY

Possibly the most renowned Galapagos bird, the blue-footed booby is often the first booby species visitors see. All through the year, Hood and Seymour Islands support large colonies.
Growing from 2.5 to 3 feet long and boasting a 5-foot wingspan, this large, whitish-brown seabird is best known for its bright blue feet; during its courtship ritual, the blue-footed booby moves these feet in a measured, stately fashion. Courtship also features wing spreading, bowing and sky pointing, with its neck, head and bill stretched straight upward. Witnessing this entertaining behavior is certainly a high point of your Galapagos journey!

At first, females and males seem virtually identical, but upon closer examination, it is easy to tell them apart; males whistle, whereas the larger females honk and have a somewhat larger pupil. Courtship, mating and nesting happen year-round, although nesting is just a euphemism for making a scrape on the ground and encircling it in a guano ring. Broods can consist of one to three fluffy white youngsters; this puffy down coat can give the impression they are bigger than their parents. In ideal years, all young will survive, but sometimes the weakest will die of starvation because the toughest one or two out compete him. « Back to top

NAZCA BOOBY

Newly split from the masked booby to receive status as its own species, the Nazca booby is completely white except for a black band adorning the edge of its wings and tail. Its facemask, responsible for the bird’s former title, is formed by a blackish area of naked skin encircling its reddish-pink or orange bill.

At 3 feet long and with a 5- to 6-foot wingspan, the Nazca, which inhabits most islands, is larger than any other Galapagos booby. Though they look similar, the calls of males and females differ; females utilize a trumpeting quack while the smaller males employ a whistle. Due to their large size, they usually nest near the tops of cliffs where they receive the greatest advantage for taking flight. In contrast to other boobies, they breed annually on a cycle that varies across the islands.

When the birds arrive to Genovesa in May, they proceed with courtship, mating and building nests. They lay eggs from August to November, most young fledge by February and the entire colony stays out on the ocean until May. In contrast, the colony on Hood remains present from September to May and individuals lay eggs from November to February. Regardless of island, the Nazca booby consistently lays two eggs, but only one will survive because even in a year with ample food the eldest sibling will expel the younger from the nest.« Back to top

RED-FOOTED BOOBY

At 2.5 feet long and with a 4.5-foot wingspan, the red-footed booby, whose red feet and blue bill with red base easily differentiate it, is the smallest Galapagos booby species. The majority of adults are brown, but 5 percent are white; this is not a sign of a new or hybrid species, but rather it is the result of a dissimilar color phase. Even though this is the most abundant Galapagos booby, it is the most rarely seen since it only inhabits distant islands like Genovesa, which supports a substantial colony consisting of approximately 140,000 pairs. To avoid competing with the blue-footed booby, which forages near shore and the Nazca booby, which feeds in-between, the red-footed booby focuses feeding efforts far out at sea.

Unlike most other boobies who favor guano-ringed ground scrapes, the red-footed builds elementary nests in trees, and lays one solitary egg. Though laying can happen year-round, it typically occurs when food is abundant. « Back to top

FRIGATEBIRD

Long scimitar wings and pronged tails make black frigatebirds appear to hang in the wind like menacing kites. As if suspended from unseen strings, they maintain one position in the sky, from which they harass terns and gulls hoping they will drop their catch. Because of a tiny preening gland, frigatebirds cannot secrete ample oil to make their feathers waterproof so they are unable to dive underwater and snag prey. Their hooked beaks, however, make it possible for them to snatch fish off the water’s surface.

Despite the sinister look of its elongated, angular beak, this huge, black seabird with a wingspan of almost 8 feet is quite elegant and streamlined. With the largest wingspan to weight ratio of any bird in the world, it is no wonder these birds are fantastic fliers.
Two species, the magnificent frigatebird and the great frigatebird, inhabit the Galapagos. Colonies exist on many islands, but the consistently energetic, magnificent frigatebird colony on North Seymour Island offers the best opportunity for viewing. Because great frigatebirds typically travel farther out on the ocean, they can usually be seen on the outer islands.

It is challenging to differentiate between these two completely black, males species. The magnificent frigatebird, which measures 3.6 feet long, is only about 2 inches longer than the great frigatebird—a virtually imperceptible difference from the field. In addition, the male magnificent’s black plumage sparkle with a purplish sheen, while the great frigate’s shimmers with a greenish shade. Both of these subtle differences are only apparent to the most experienced eyes.

Fortunately, it is easier to differentiate between females. Magnificent females have a blue eye-ring and white underparts adorned with a black throat while great females have a reddish eye-ring and entirely white underparts, including the throat. Identifying the females allows you to assume their mates are the same species. Both juveniles have white underparts and white heads.

Like many seabirds here, the frigatebird puts on a remarkable courtship display. The females visibly search out and select mates by taking flight over the rookery to examine males, who band together in groups. When a female flies low circles overhead, males respond in kind by inflating the scarlet gular pouches that dangle below their necks. After approximately 20 minutes, these heart-shaped, football-sized balloons reach full inflation. Typically, the male displays it heavenward in an effort to entice to attract females as they pass overhead. He also makes loud drumming and clicking sounds and vibrates his wings rapidly to further entice females. Once paired, the couple begins building nests. Frigates are known for stealing twigs from nearby nests so while the male searches for twigs, the female remains at the nest site to protect it from thieves.« Back to top

GREAT BLUE HERON

Though called ‘blue,’ this heron, the biggest in the Galapagos with a 6.5-foot wingspan and 4.5-foot-long-body, is actually a largely gray bird readily identified by its lengthy legs and pronounced size. Similar to many herons, the great blue typically stands with its head stooped over toward its shoulders, a position it sustains while flying, with its elongated legs trailing behind.

Great blues gravitate to the rock-strewn coasts of a majority of the archipelago’s islands, frequently remaining still while waiting for fish to pass. Other food sources include lizards, birds and juvenile marine iguanas. Inclined to live on their own or in pairs, great blue herons sometimes form a tiny colony supporting at most six nests. Breeding occurs all year and nesting typically takes place in mangroves.« Back to top

YELLOW-CROWNED NIGHT HERON

This common, stout, gray heron, distinguished by a yellow crown capping a black and white head, feeds at night. During daylight, it frequently makes an appearance in shady spots along every island’s shore. Since it is nocturnal, it has bigger eyes than other herons. Yellow-crowned night herons breed in pairs and make nests year-round underneath rocks or in mangroves.« Back to top

COMMON EGRET

Black feet and legs and a yellow bill help with identification of this large completely white heron with a wingspan of 4.6 feet and a body that is 3.5 feet long. Contrary to its name (it’s also called the American or great egret), visitors see this heron less frequently than the great blue even though it inhabits comparable habitats and can occasionally be found inland.« Back to top

CATTLE EGRET

From a distance, you can tell that this comparatively petite, white heron—1.7 feet long with a 3-foot wingspan—has a stockier build and shorter neck than the common egret. Get closer and its yellow legs and feet become more obvious. Unidentified in the Americas until the 1800s, the first instance of a cattle egret in the Galapagos wasn’t recorded until 1965. Originally from Africa and southern Eurasia, the cattle egret can now commonly be seen in pasturelands and is most often seen in the Santa Cruz highlands.
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GALAPAGOS HAWK

The only raptor breeding in the Galapagos, these predatory native hawks, who are dark brown with the exception of their yellow feet, legs and ceres (the fleshy spot at the bottom of their bill), have wings that are broader than comparably sized seabirds. Juvenile birds are heavily mottled and a lighter brown.

Because they don’t have any natural enemies, they basically act fearless which has resulted in hunters killing them to extinction on various islands, including Genovesa, Seymour, San Cristobal, Santa Maria, Baltra and Daphne. Hunters greatly reduced their numbers on Santa Cruz, too, and it’s estimated that only approximately 150 pairs continue to live in the Galapagos. Visitors are most likely to see the Galapagos Hawk on Fernandina, Santa Fe, Bartolome, James, Hood and Isabela islands.

Breeding occurs more frequently from May to July, but as a species, they breed year-round, utilizing cooperative polyandry, a technique where one female mates with at least two males and all adults help to raise the young. Differentiating the sexes can be challenging, but generally, females are larger in size than males.« Back to top

LAVA & STRIATED HERON

A small, dark bird with a 2-foot wingspan and yellow-orange legs, the lava is the only heron endemic to the archipelago. Its deep green feathers help hide its presence while it utilizes the lava-laden shorelines to hunt surreptitiously for prey; juveniles, however, are streaked and brown. Breeding is possible all year, but the span between September and March is the lava heron’s preferred time for breeding. Though sometimes they are found in clusters of two or three, they usually build solitary nests located in mangrove trees or underneath lava outcrops. Though they are often present along the rocky coasts of all islands, their solitary nature and camouflage make them challenging to see. Our naturalist guide can easily help you spot one.

Though they are approximately the same size, the striated heron is paler in color than the lava heron. Ornithologists don’t know if these two similar creatures are distinct species, if they can hybridize or if the lava heron is just a variety of the striated heron. « Back to top

LAVA GULL

Biologists estimate that approximately only 400 pairs of lava gulls, the world’s rarest species of gull, exist today. They are, however, broadly distributed throughout the Galapagos so your chances of seeing one are good. These lone nesters, who range from dark gray to black and measure 1.8 feet long, breed year-round.« Back to top

BROWN NODDY TERN

Dark brown with a white forehead, the brown noddy tern frequently feeds with pelicans, often trying to grab fish scraps coming out of the pelican’s bill as water drains from it. In an effort to get a more optimal position, this tern has even used a pelican’s head as a perch. This bird, which is 1.27 feet long with a wingspan of 2.5 feet, nests year-round in tiny colonies located in caves and on cliffs. « Back to top

GALAPAGOS DOVE

Native to the islands, this beautiful, colorful 8-inch long dove has a reddish hue underneath, brown upper parts, neck patches that are green, blue eye rings and red feet and legs. They breed all year, laying two eggs in a jumbled twig and grass nest that rests under rocks or entangled with an abandoned nest left by a different species. During incubation, adults may wander away from the nest while feigning injury. This behavior, developed to lure predators away from eggs, evolved long before doves came to the Galapagos and remained in use even though it isn’t very useful on the island.« Back to top

DARWIN’S FINCHES

Darwin’s finches, named due to their role in Charles Darwin’s theories on evolution, are ostensibly the most renowned land birds of the Galapagos. Fascinated with diversity found among the thirteen species and the speed with which they evolved from a common ancestor to adapt to the varied supply of food available on individual islands, Darwin discovered that these adaptations mainly showed up in the shape and size of beaks.

Though these 13 finches are the most well-known and scientifically important Galapagos birds, they are not very remarkable looking. Endemic and typically easy for visitors to spot, it takes an expertly trained eye to differentiate the thirteen species who scientists believe descended from a shared ancestor. The differences in distribution, plumage, feeding habits, body size, beak size and shape helped inform Darwin’s theories.

Hood only supports the small ground finch, the warbler finch and the large cactus finch, which has a massive bill; thus, this island affords visitors the ideal opportunity to distinguish among these three species. The other species found across the islands are harder to distinguish from each other because of their similarities and idiosyncratic behaviors. For instance, some tree finches are found on the ground, some ground finches spend time in the trees, and cactus finches have been known to spend time in an array of habitats, including cacti.

To see each of the 13 species, you’ll need to travel a bit because certain species are not widely distributed. The medium tree finch lives only in the Santa Maria highlands while the mangrove finch exclusively exists on Isabela and Fernandina. Of islands open to visitors, the large cactus finch solely inhabits Genovesa and Hood. The other finches are more widely distributed.« Back to top

Explore the native reptile species in the Galapagos, including the famed giant tortoises and prolific marine iguanas.

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Reptiles

Mammals dominate life in many parts of the planet, but on the Galapagos, reptiles rein largely due to the hot, dry climate that suits their needs. The Galapagos supports 25 native species of reptile (19 endemic) and early on Charles Darwin labeled the islands a “paradise” for reptiles, cold-blooded creatures with slow metabolisms that don’t necessitate a large supply of food and skin that offers sun protection. Without many mammals on the islands, reptiles on the archipelago encounter negligible amounts of predation and competition, making them easier for those traveling to the Galapagos to see and enjoy at very close range.
Click on the links below to navigate to each species.

PACIFIC GREEN SEA TURTLE

The Pacific green sea turtle breeds and lays eggs in the Galapagos, but it is not endemic to the islands. They are called “green” because of the color of their flesh, and are one of the largest of the turtle species, ranging from 2.5 to 5 feet in length and weighing up to 450 pounds.
These turtles have paddle-like limbs, the shape of which aids them in becoming proficient swimmers. The carapace of the green sea turtle can be olive to brown, or sometimes even black, depending on the geographic location of the species. Males are larger than females and have longer tails, which extend well beyond their shell.
Green sea turtles cannot pull their heads and limbs inside of their shells, which makes them more vulnerable to predators. They are mostly herbivorous and they spend most of their time feeding on algae in the sea and on the grasses that grow in shallow waters. As juveniles, they eat plants and other organisms such as jellyfish, crabs, sponges, snails and worms. As adults, they are strictly vegetarians.
Green sea turtles are quite promiscuous during the breeding season, especially between November and January, when mating activity can often be observed in the water. Nesting occurs at night on many of the sandy beaches of the islands mainly from December to June, peaking in February. The female digs a hole in the sand above the high tide mark and deposits several dozen eggs, a process which takes about 3 hours. She then covers them with sand to protect them from the sun, heat and predators and returns to the ocean.

The newly laid eggs incubate in the sand for 50 to 60 days. The temperature of the nest determines the sex of the turtles, with cooler nests producing a clutch of males, and subsequently, warmer nests producing more females. On a clear, moonlit night, the hatchlings will dig themselves out of their nests and scramble towards the water. Once away from the protection of their shells, they are extremely vulnerable to predation. Only 2 inches long, the tiny, helpless turtles have a treacherous journey, struggling to avoid ghost crabs, sea birds and fish on their way to the open sea. Once they reach their destination, the turtles swim away for years. Almost nothing is known about this period of their lives, until they again return to nest at the same beach in which they were born. « Back to top

MARINE IGUANA

The marine iguana is the only sea-going lizard in the world and is found on the rocky shores of most of the islands. This iguana has a blackish skin, which in males can change to startling blues and reds during the breeding season. Breeding occurs at different times on different islands; the males on Española are colorful year-round. Marine iguanas are colonial, often seen piling atop one another, but when breeding, the larger males become territorial and aggressive, butting and pushing their rivals. Mated females lay two to four eggs in a sandy nest that they guard fiercely, although the hatchlings, which emerge after 3 or 4 months, are not given much parental protection.

Marine iguanas feed mainly on intertidal seaweed, although mature males have been recorded offshore at depths up to 40 feet and submerged for over an hour. The row of spines along the entire length of their backs, their scaly skins, their habit of occasionally snorting little clouds of salt spray into the air, and their length, which can reach almost 3.3 feet, make them look like veritable little dragons.« Back to top

LAND IGUANA

Both land iguanas found in the Galapagos look almost identical; these two species are yellowish in color and bigger than their marine relatives; adults weighing as much as 13.25 pounds have been recorded. The Galapagos land iguana lives on South Plaza, Isabela, Santa Cruz, Fernandina and Seymour Islands, with South Plaza offering the best viewing opportunities. Previously, they inhabited a majority of the archipelago, but hunting and competition from non-native species such as goats, rats, pigs and dogs, which prey on iguana eggs, led to their demise on many islands. The similar looking Santa Fe land iguana, limited to Santa Fe Island only, is, on average, slightly bigger and more yellow than the Galapagos land iguana and has more pronounced spines. They can exceed 3.3 feet in length.

Both land iguana species choose prickly pear cactus as their preferred food, often needing to stand on their back legs to feed on the yellow blooms and juicy cactus pads, which they can eat whole and with spines intact due to the fact that iguanas have leathery mouths.

Land iguanas are known to live for at least 60 years. They reach sexual maturity between 6 and 10 years of age. Mated females lay between five and fifteen eggs, and like the marine iguana, they defend their nests until hatching occurs. The breeding season for land iguanas occurs during different months on different islands.« Back to top

LAVA LIZARD

Less spectacular than the iguanas are the seven species of lava lizards, which are frequently seen scurrying around. They can reach up to 1 foot in length, but are usually smaller. Their most distinctive behavioral patterns are rapid head bobbing and push-up stances, which are performed in order to defend their territories and to assert dominance.

The male is larger than the female and is strongly patterned with yellow, black and brown coloring. The female’s design is less intricate, but instead, stands out with her flaming red throat. It is easy to separate the seven species of lava lizard by geographical distribution. Six of the islands have their own endemic species that are found nowhere else in the world.« Back to top

GIANT TORTOISE

Of all the wildlife in existence today, the giant tortoise best symbolizes the Galapagos Islands. In fact, the word Galapagos is Spanish for “shape of a saddle,” which is what many tortoise shells actually resemble. Fourteen subspecies, each in some way distinctive to the island of its residence, comprise the sole giant tortoise species. Of these fourteen varieties, three are extinct. One of the best ways to distinguish those still in existence, apart from geographic distribution, is by the differences in the shape of their shells. These differences, as described in The Voyage of the Beagle, contributed to the development of Darwin’s theory of evolution:

“I have not, as yet, noticed by far the most remarkable feature in the natural history of this archipelago; it is, that the different islands, to a considerable extent, are inhabited by a different set of beings…I never dreamed that islands, about 50 or 60 miles apart, and most of them in sight of each other, formed of precisely the same rocks, placed under a quite similar climate, rising to a nearly equal height, would have been differently tenanted; but we shall soon see that this is the case. It is the fate of most voyagers, no sooner to discover what is most interesting in any locality, than they are hurried from it; but I ought, perhaps, to be thankful that I obtained sufficient materials to establish this most remarkable fact in the distribution of organic beings.”

There are two major shell designs of the giant tortoise. The upper half of the shell, called the carapace, is distinct from the plastron, or lower half. The “dome-shaped” carapace is found on larger varieties of tortoise from Santa Cruz and the Alcedo Volcano on Isabela, where the large tortoises feed on the relatively lush vegetation. The “saddleback” carapace, found on the Hood (Española) and Pinta varieties, allows for the tortoise’s long neck to emerge, permitting it to feed on the hard-to-reach vegetation of the drier islands.

Tortoises are vegetarians and their diet includes grasses, forbs and leaves on bushes. They have been known to eat several peculiar foods such as stinging nettles and crab apple-like fruits of the manzanillo tree, which burn human skin. They also have very slow digestive systems; it can take their bodies up to 3 weeks to fully process a meal. Scientists guess that the tortoise’s life span is somewhere around 150 years.

The giant tortoise reaches sexual maturity at about 40 years of age. Between the months of January and August, towards the end of the rainy season, the male begins sniffing the air for a female’s scent. He will posture and heave competitive males to demonstrate his dominance, and then begin the search for a female mate. Once a female is found, he chases her down and begins his style of courtship with intimidation. He rams her with the front of his shell and nips at her exposed legs until she draws them in, immobilizing her. He then mates with her. Males unsuccessful in finding a female partner have been known to attempt to mate with other males, or even with appropriately shaped boulders!
Having mated, the female looks for a dry, sandy area in which to make a nest. Starting a process that takes up to several days, she uses her hind legs to dig a hole approximately one foot deep. Between two and sixteen eggs are laid and are then covered with a protective layer of mud made from a mixture of soil and urine. The eggs take about 4 to 5 months to develop, and hatchlings usually emerge between December and April. When the eggs hatch, the baby tortoises are forced to fend for themselves, most dying within the first 10 years of life.

Known for their ability to go without eating for extended amounts of time, the tortoises voyaged to the islands aboard rafts of vegetation. They have tremendous water storage capacities, which enable them to survive the long, arid season. This special attribute became a curse when buccaneers and whalers, keenly aware that the animals could withstand long voyages up to a year without food or water, harvested them by the thousands for their meat. They were stored upside-down in the bilge, ready for slaughter when fresh meat was on the menu. As a result of their endemic capture, only 15,000 remain today.

Presently, at the Charles Darwin Research Station, a tortoise-breeding project has achieved successful results and increased the depleted population by introducing these animals into the wild. The research station provides us with the easiest and most convenient facility in which to view both tiny yearlings and full-grown adults. Although the tortoises are in enclosures, visitors are permitted to enter to get a closer look at these giants, some of which can reach up to 550 pounds and could quite easily carry a full grown man on their back. Adults weigh over 1,000 times more than newborn hatchlings, which weigh-in at less than half a pound.« Back to top

Invertebrates, including insects, crabs, and snails, make up an estimated 51% of the total biodiversity of the Galapagos Islands.

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Invertebrates, Insects, & Fish

A plethora of insects, invertebrates and fish inhabit the Galapagos Islands. In fact, more than 1,700 species—two-thirds of the invertebrates living here—are insects. Ten species of butterflies comprise the most showy insects on the archipelago, but there are also ants, beetles, centipedes, dragonflies, grasshoppers, spiders and scorpions, among others. Tide pools reveal a variety of invertebrates including crabs, starfish, anemones, lobster, sea urchins and corals, while the water, which fluctuates between temperate and tropical temperatures, rewards visitors with a mix of diverse fish that include sharks, rays, stingrays and colorful tropical fish like the blue parrotfish and white-banded angelfish.
Click on the links below to navigate to each species.

INSECTS

Insects are the most numerous animals in existence. Literally millions of species are found in the tropics, a little over 1,000 of which are thought to inhabit the Galapagos. This comparatively small number is very reflective of the difficulty that insects had in crossing the almost 620 miles of ocean to colonize the islands.

There are not many colorful insect species in the Galapagos. There are a few species of butterflies, ants, grasshoppers and wasps, and many more representatives of the beetle and moth groups. There is also only one species of bee, one preying mantis and two scorpions in the Galapagos. The scorpions are rarely encountered and though their sting can be painful, they are not normally dangerous.« Back to top

INVERTEBRATES

In terms of invertebrates (animals lacking a backbone), most visitors first notice a small crab with a bright red top and blue underside because the Sally Lightfoot crab is ubiquitous on most rock beaches. Also present on rock beaches is a black crab, which blends well with the lava background. These small, well-camouflaged crabs are actually young Sally Lightfoots. The adults, however, are far from camouflaged and must remain alert and vigilant to escape predators. If humans approach them, Sally Lightfoots will immediately dash to safety and are even able to scurry across tide pools by staying on top of the water. If you remain still crabs will draw near, a fact that herons, who prey on Sally Lightfoots, use to their advantage during predation. Keep an eye out for a lava heron waiting motionless amid rocks on the beach. If a crab moves within striking distance, the bird will thrust toward the crab to grab it. If the heron succeeds, he will devour it, but only after shaking it and knocking it against rocks to make its legs fall off.

Other crab species inhabit the Galapagos, including the ghost grab, a pale, sand colored creature that stares at you with unusual eyes situated at the terminus of long eyestalks. It leaves a characteristic pattern of sand balls that are seen on most sandy beaches.
Tide pools also support the hermit crab, a crustacean who makes its home by carrying an empty seashell on its back. When a juvenile hermit crab outgrows its protective shell, it finds a larger one and grows into that one. This “moving house” occurs several times before the hermit crab reaches adult size.

At low tide, tide pools offer a good opportunity to study marine invertebrates. Starfish, sea anemones, sea urchins, marine snails, barnacles, chitons and limpets are often found. Venture deeper into the water with snorkeling gear to see many more creatures, including sea cucumbers, octopus and corals. If you poke around some of the rocky underwater crevices, you may even encounter lobster. Be careful where you poke though, because you may encounter the sea urchin, which has beautiful iridescent black spines that are long, brittle and needle-sharp.« Back to top

FISH

Scientists have recorded over 300 species of fish from more than 90 families in the Galapagos, and it is expected that there are still more waiting to be discovered. Over 180 of these fish are found in much of the tropical eastern Pacific, and about 50 species are endemic. Godfrey Merlen’s Field Guide to the Fishes of Galapagos is available in Quito, and is highly recommended for snorkelers. This booklet describes and illustrates over 100 of the most frequently seen species. One interesting fact that you may read is that many species of tropical fish change their color and shape as they age; a few can even change their sex midway through life. This certainly makes identification confusing!

Snorkeling in the Galapagos is a rewarding experience, with schools containing thousands of tropical fish routinely seen. Your naturalist guides can help to identify the more common species. These include blue-eyed damselfish, white-banded angelfish, yellow-tailed surgeonfish, moorish idols, blue parrotfish, concentric puffer fish, yellow-bellied triggerfish and hieroglyphic hawkfish, to name but a few, and to give you some idea of the variety in form and color.

The one type of fish that swimmers are often most interested in is the shark. There are several species found here, the most common of which being the white-tipped reef shark and the Galapagos shark. Hammerheads are also occasionally seen. Sometimes viewed by snorkelers, their speed and grace underwater is extraordinary. In fact, one of the best reasons to snorkel in the Galapagos is the chance of seeing these magnificent animals.

Another kind of fish that provides the snorkeler with a real thrill is the ray. Again, there are several species, all harmless with the exception of the stingray, which sometimes basks on the sandy bottoms of the shallows and can inflict an extremely painful wound to waders and paddlers. It is a good idea to enter the water by shuffling your feet along the sandy bottom. This gives stingrays the chance to swim away before you step on them. Less frequently seen is the giant manta ray, which is usually found in deeper offshore waters. You are most likely to catch sight of one as it leaps out of the water and falls back with a loud slap. With a maximum spread of 20 feet, it makes a huge splash as it hits the water.« Back to top